Reversible-circulation internal-fan kiln



REVERSIBLE CIRCULATION INTERNAL FAN KILN Filed July 21, 1921 2 Sheets-Smart l 'Ao/f The/en INVENTOR.

BY m m w A TTORNEYS.

finally ll 9 E9240 fl' R. THELEN REVERSIBLE CIRCULATION INTERNAL FAN KILN Filed July 21, 1921 2 Sheets-shea 2 W INVENTOR.

BY 1 t" ATTORNEY Patented duly ll, Wfid.

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wwwww r arent REVWSIBLE -cmcur.arron INTERNAL-FAN KILN'.

Application filed July 21 1921. Ferial No. 486,564.

(FILED manna "run Aer or Manon To all whom it may concern:

Be it known that I, Rom THnLnN, a citizen of the United States of America, and an employee of the Department of Agriculture, residing in Madison, Wisconsin (whose postofiice address is Department of Agriculture, Madison, Wisconsin), have invented a new and useful Reversible-Circulation Internal- Fan Kiln.

This application is made under the act of March 3, 1883, chapter 143 (22 Stat, 625), and the invention herein described and claimed may be used by the Government of the United States, its oflicers and employees, and by any person in the United States without payment to me of any royalty thereon. I hereby dedicate the same to the free use of the Government-and the people of the United States.

My invention relates to a compartment kiln in which the main circulation is internal and is produced by means of a row of internal fans. It is an improvement in the art of drying in that it combines three very 25 advantageous features; namely, (1) a reversible circulation by means of which the drying is made more uniform and the drying time out down appreciably, (2) an unusually uniform distribution of the air currents, (3) a mechanical means of producing the circulation which is very simple and very efficient, it being generally recognized among those skilled in the art that disk fans are the most economical means for the movement of large quantities of air at relatively low pressures.

The operation of the kiln will be evident from an inspection of the accompanying drawing, which shows in- Fig. 1 a sectional side view of the kiln, and in Fig. 2 a lon tudinal cross section taken directlyunder t e horizontal portion of partition H in Fig. 1. Referring to the drawing, a row of disk fans A is mounted in a partition wall E, running the full length of the kiln. These disk fans are novel in the method employed for cooling the direct connected motors driving them. Each motor N is-surrounded by a suitable casing B. Each one of these casings is reasonably air-tight with the exception of outlet ducts K suitably arranged, and an inlet pipe C through which fresh outside air is supplied from the blower D. This fresh air after passing around the motor to the other.

3, 188?, 22 STAT. In, 625.)

passes into the kiln through the outlets K and can be made to serve a dual purpose, not only keeping the motors cool and dry but also serving to reduce the humidity in the kiln as needed. The quantity of air assing through each duct C can be any suitable means.

The motors are provided with the necessary wiring so that they may be reversed at will without entering the kiln. The motor Wiring may be carried through the ducts C and thus protect it from the atmos here of the kiln. A switch 9 is provided tor operating motor N. Another switch M is provided for starting, stopping and reversing the disk fans A. By supplying air under a slight ressure to the casings B any leakage throug the casingstakes place outward whereas in self-cooled motors, in which a slight suction is established in the casing, the leakage is inward, which is especially deleterious during the periods when the kiln is filled with steam at high temperature. The pressure system is in this regard superior.

The partition H extends the full length of the kiln on both sides and below the lumber pile and shuts off the fan chambers from the lumber entirely except through the openings I of which there are a comparatively large number. The dampered vents J J are to be used to assist in reducing the humidity at times when this cannot be accomplished with sufficient speed by means of the air blown in through the ducts C. The heating pipes G G and the steam spray lines F F can be located wherever convenient. The particular location chosen for the heating coils has the serving to baffle and distribute the air entering or leaving the vertical chambers L L which act respectively as plenum chambers or vacuum chambers, depending upon the direction of the air flow in the kiln.

The steam jet lines F F serve to increase the humidity of the atmosphere in the kiln, both during normal operation and during steaming treatments. The chambers L are intended to be of sufiicient width to reduce the velocity head and friction of the moving air to a point at which it will not interfere with the uniform, horizontal movement of the air through the lumber pile from one side The reversing feature permits contro led by specific advantage of tld ' the air ts be moved either to the right or to with a receptacle containing the material to be dried of a series of motor-driven reversible fans mounted in a row lengthwise of the interior of said receptacle and a com- 15 mon means for supplying cold air to cool all of the motors.

ROLF THELE N. Witnesses:

RAY C. Tu'rrnn, E. C. SHERRARD. 

